Millions of people suffer from thrombotic or atherosclerotic occlusions in blood vessels. Such occlusions restrict the blood flow through the vessel, and if left untreated, these occlusions may lead to a heart attack, or even death. A variety of available medical devices have been manufactured to treat occlusions in a blood vessel within a patient's body. For example, directional atherectomy and percutaneous translumenal coronary angioplasty (PTCA) with or without stent deployment have been found useful in treating patients with coronary occlusions, as well as occlusions of other vessels. Angioplasty utilizes an expandable balloon on a catheter which exerts a mechanical force on the vascular wall to enlarge the luminal diameter of an occluded vessel. In some medical procedures, a prosthetic device, such as a stent, is expanded within the blood vessel at the location of the occlusion in order to provide patency/integrity through the lumen of the blood vessel at the location of the occlusion.
Some vascular occlusions can be difficult or impossible to cross with existing angioplasty catheters and stent delivery systems. For example, in some instances the occlusion may extend substantially across the lumen of the blood vessel, or may even completely block the lumen of the blood vessel in some cases. In such instances, it may be difficult or impossible to advance a conventional catheter, such as the balloon of a conventional angioplasty catheter (i.e., POBA) and/or a stent of a stent delivery system, across the occlusion.
Therefore, a need remains to provide a catheter system to aid in crossing vascular occlusions with a balloon and/or a stent of a balloon catheter. Namely, it would be desirable to provide a means for facilitating advancement of a balloon, stent and/or other working element of a catheter through the restricted opening of a vascular occlusion of a blood vessel.